Japanese patent publication No. 56-14699, published Apr. 6, 1981, discloses compositions comprising 100 parts by weight of certain aromatic polyesters and not more than 100 parts by weight of a polyamide. Such compositions are said to have improved mold processability, chemical resistance, low temperature resistance, and oil resistance. This publication notes that processability improves when the amount of polycaprolactam is 50% by weight or greater, but the physical properties drastically deteriorate; and that similar trends are observed with other polyamides as with polycaprolactam.
Japanese patent publication No. 54-144455, published Nov. 10, 1979, discloses blends of 0.1-10 parts by weight of a non-crystalline polyamide with 100 parts by weight of an aromatic polyester, which blend is said to have heat-resistant deformation, mechanical strength, transparency and improved processing properties.
Japanese patent publication No. 54-141840, published May 11, 1979, discloses compositions similar to that described immediately above except that the aromatic polyester contains a component derived from a trivlanet alcohol. Such blends are said to have improved moldability without impairing the heat distortion resistance, mechanical properties, transparency and stress cracking resistance of the blends.
Japanese patent publication No. 52-98,765, published Aug. 18, 1977. discloses compositions comprising 100 parts by weight of certain aromatic polyesters and more than 100 parts by weight of a polyamide. Such compositions are said to have excellent moldability, chemical resistance and heat resistance.
U.S. Pat. No. 4,206,100, granted June 3, 1980 to Kyo et al, discloses resin compositions consisting essentially of an aromatic copolyester, a polyamide and certain metal compounds. Such compositions are said to have improved mechanical characteristics, including improved impact and brittleness at thin walled portions.
U.S. Pat. No. 4,187,358, granted Feb. 5, 1980 to Kyo et al, discloses compositions similar in identity and properties to those described immediately above, except that these contain an ionomer instead of the metal compound.
U.S. Pat. No. 4,171,330, granted Oct. 16, 1979 to Kyo et al, discloses flame retardant compositions comprising an aromatic copolyester, a polyamide, a polyalkylene phenylene ester or ester ether, and an aromatic halogen.
U.S. Pat. No. 4,052,481, granted Oct. 4, 1986 to Asahara et al, discloses compositions substantially as described immediately above except without the aromatic halogen.
U.S. Pat. No. 3,835,098, granted Sept. 10, 1974 to Hoeschele et al, discloses thermoplastic elastomeric copolyester compositions having improved elastomeric, physical and stability properties, which compositions comprise a blend of such copolyesters with at least one polycarbodiimide.
U.S. Pat. No. 3,193,522, granted July 6, 1965 to Neumann et al, discloses polyesters stabilized against hydrolysis with polycarbodiimides.
H. Ulrich, Polyurethane Stabilizers, Journal of Elastomers and Plastics, Vol. 18, pp. 147-158 (July 1986), discloses the use of polycarbodiimides to improve the hydrolytic stability of polyester based polyurethane elastomers.
None of the references listed and discussed above disclose the particular blends of the present invention, or the unexpected improvement in impact strength that can be imparted to polyarylate-polyamide blends by including in such blends certain polycarbodiimides.